Instrument for rotary wing aircraft



May 10, 1949. J. 5. PECKER INSTRUMENT FOR ROTARY WING AIRCRAFT 2 5 mpg H. ,5. Z a v m oh HQ a a .M Q v E sWmm F o o w E. N m/km Patented May 10, 1949 UNITED STATES PATENT OFFICE- ifisTfitdfifiNgjgggfggTnhY WING J osepli Pe'cker, Los'Angeles,'Ca1i.- Application January 18, I946", SeriafNo. 641,959

2 Claims. i

This" invention relates to an instrument for helicopters, and more particularly to an instrument for indicating instantly to the pilot various operative conditions of the helicopter rotor.

In theory, at least, the performance of a helioopter, in hovering or any other attitude of flight, is at highest efiiciency when a given R. P. M. of the rotor is accompanied by e specifie pitch angle of the rotor blades. If, for eXainpIe, the pitch angle, 1. e. the angle" of attack, or the rotor blades is less than the optimum for a given engine R. P. itwould be necessary for the L'iilot' to adjust hi's throttle to increase the engine R. P. M. conversely; if fore iven engine n. P. the rotor blade angle of attack" is in excess or the ootimum', instability would resm't. When, howeve the blade angle or attack and the engine R- P. M. are roperly oorreiated, the helicopter will hover most emcientiy. It is true, of course, that experienced helico ter" pilot's ultimately attam a feel by which they instinctively adjust the mm of attack of the blades to a given R. P. or vice verso, without the necessity of manipulatin both the engine and hlade eontrois. The less experienced pilot, however, often: has difiico-Ity in attaining. the most ancient related angle or attack and engine R. P, and while he may be able to maintain the helico ter in statio ary or hovering flight, it often happens that he does so only by use of excessive expenditure of engine power, hence" fuel consumption.

It is aooordm'ely important for either the inexperrenoed or ex erienced pilot to have some means of quickly indicating to hini whether or not his engine and rotor blade controls are not only correlated for hoverihg,. but more important, are oor'reiated' at predetermined optimum values,

wherein the helicopter performance is most eth- Then too, if the pilot is attempting" to hover in the face or aw'ind, he must of necessity ddju'st the angle of intimation of the rotor, so as to impart to the heifcopter a projecting impulse equal and opposite'to the force of wir'id so as to obtain a; zero: resultant to permit hovering. Of course, under static wind'conditions, the virtual none of rotor rotation is essentially normal to the of rotation. p U

It is then among the ohieots of my invention to provide an instrument for install atfdn with certain of the helicopter" rotor eont-rois, whereby the optimum settingsthereof can readily he made and indicated, to the end of maintaining the helicopter in hoverin condition at highest efficreney; Another object is to provide such e device which is thoroughly simple and practise-i, sturdy and reliable use; and of ready utility to inexperienced, as well as experienced pilots. Other objects wi'lT be in port apparent; and in part pointed out hereinafter; 1

In accordance with one form of my invention, the helicopter is p'mvided with a mamial control for adjusting the angle of attack of the rotor blades, another control for adjusting the angle of inclination of the rotor, and still another attached to the throttle oi the engine. Attached to each of these controls is a. meohanisniwhereby manipulation of shirts immediately indicated on a dial, the indioetorsfor each control being so arranged relative" to the grad-nations on the dial that coincidence of the indicators, or any other predetermined relationship thereamong, immediately indicates to the pilot that the controls areset at optimum values; if e". values at which most emcie'nt performance is being ohtained;

In the drawing,

Figure 1 is a fragmentary schematicelevation, partly section, of the helicopter engine, rotor, engine and rotor controls and control condition indicators; and, 7 H

Figure 2 is at plan view of the helicopter hand Wheel.

In Figure I, th'e helicopter engine, generally indicated at I'D, has connected thereto a drive shaft H, to which is secured in conventional manner, a rotor [2, having blades r31 connected thereto the usual fashion to permit pivotal and flapping movement thereof, relative to the rotor nub. It will, of course, be understood that the rotor may be equipped with conventional cyclic control apparatds not shown herein as not relating to the invention hereinafter disclosed.

The angle or inclination" of rotor [2 may be controlled by manipulation of a swash late- M. The angle of attack of blades F3 may be controlled by manipulation of a; slip ring i5, while the engine R. P. M. may he controll'ed by manipul'ation of a throttle lever it". These several controlling elements may be manipulated resp'e'otively by foot levers H, I8 and f9", it being understood; of course that hand levers or other manually operable members may he used, if desired. Thus foot lever H is pivotally mounted on a stud 20,, su1tah13r seouredto the fuseiage (not shown), the lowerend [1d of this lever being pivoteily connected to a fork 2'1 adjustably' secured to one end of'a pull her 22 or the like. The other end of this poll bar: adjustelh'ly carries a fork 23 pivotally ettachedes by a pin 24, to one. arm' 25a or a hen crank 25, pivotdlly mounted on a shaft or pin 26 secured to the fuselage. The other end 251) of bell crank is adjustably connected to the lower end of a vertical pull bar 21, as by a fork 28, the upper end of this vertical pull bar being pivotally connected to an extension arm l4a of swash plate M, by a fork 29. The swash plate is, of course, operatively connected to the rotor in any well known manner so as to effect cyclic control thereof.

In similar fashion, foot lever 18 is connected by a pull bar to a pivoted bell crank 3| which, by way of a vertical pull rod 32 is connected to one arm of a lever 33, centrally pivoted as at 34. The other arm of lever 33 may be in the form of a yoke 33a, having inwardly directed pins 33b, which ride in a reduction of slip ring 15. The slip ring is attached to the rotor blades in any suitable manner so as to control the angle of attack thereof.

Foot lever I9 is directly connected by a pull bar 35 to throttle [6.

It will, of course, be understood that the dis closed operative connections, i. e. the pull bars and bell cranks, between the foot pedals and their respective controlling members are purely illustrative herein, as there are many obvious equivalents thereof. For example, the pedal motions could be effectively transferred by means of ap propriate cables, pulleys and springs, or, if a more elaborate system were desirable, servomotors could be used. In other words, my invention is not to be limited to the specific means disclosed for transferring the motions of the foot pedals.

It may now be seen that if foot lever ll is rocked counterclockwise, swash plate I4 is rocked clockwise, thus to vary the rotor inclination. counterclockwise movement of foot lever J8 results in downward movement of slip ring l5, with a resulting variation of the angle of attack of the rotor blades [3. In like manner, counterclockwise movement of foot lever l5 advances throttle l6.

Conveniently mounted in the cockpit of the helicopter is a fixed brace 36, having an angularly and downwardly extending hub 31, on which is rotatably mounted the upper end of a tube 38 from which extend the attached spokes 33 of a hand wheel 40. Adjacent the lower end of tube 38 is a drum 4'l, to which is secured one end of a cable t2, which cable is conveniently carried over a suitable number of idlers 43, and has its other end attached to conventional anti-torque controls (not shown).

Disposed within tube 38 is a sleeve 44, having an enlarged upper end 45, rotatably carried by the inner periphery of brace hub 31. To the lower end of sleeve is attached a hub 36, in which is cut a spiral cam slot 41, adapted to receive the inwardly directed pins 48 of a yoke 46, pivotally fastened, as by a pin 53, to the fuselage. The other end of yoke 49 comprises an arm 5 I, which is pivotally attached, as by a fork 52, to one end of a pull rod 53, the other end of this pull rod being attached to foot lever I8.

It follows then, that when foot lever i8 is manipulated, e. g. rocked counterclockwise, yoke 49 is rocked clockwise. Cam slot 41 in sleeve hub 46 is so positioned that upon such clockwise movement of yoke 49, its pins 48, which ride in the cam slot, impart rotary movement to the hub,

and accordingly to sleeve.45, thereby rotating a pointer 54 fastened to the upper end of the sleeve. This pointer registers on the graduated surface of a dial 55 (see also Figure 2) marked on a flange-like portion 56 of brace 36. It will accord- 4 ingly appear that the pilot can immediately read on dial 55 the value of the setting of slip ring 95, and accordingly the value of the angle of at tack of the rotor blades.

Within sleeve 44, and rotatably supported relative thereto, is a second sleeve 51, to the lower end of which is attached in any suitable manner a hub 58, having cut therein a cam groove 58, generally similar to cam groove 41 in hub 4-6. Extending into this groove 59 are the opposed inwardly directed pins 60 of a yoke 65, pivotally mounted as at 52, and having an arm 63 pivotally connected to one end of a pull rod 64. The other end of this pull rod is pivotally connected, as at 65, to the foot lever l1. Thus, as in the case of foot lever l8, counterclockwise movement of foot lever 11 results in rotation of hub 58, so that the inner sleeve 51 is rotated as foot lever i1 is moved. To the upper end of sleeve 51 is attached a pointer 56 which, as shown in Figure 2, registers along a graduated dial 81, marked on the face of brace flange 56. It being remembered that manipulation of foot lever I1 controls swash plate it and accordingly the angle of inclination of rotor if, it may be seen that the pilot can at any time read the momentary value of the rotors angle of inclination.

In generally similar fashion, the value of the setting of throttle It may be determined. Thus within inner sleeve 51 is rotatably disposed a shaft 61, the lower end of which carries a hub 66, provided with a cam slot 69, similar to the slots hereinbefore described. This slot 69 receives the opposed pins 10 of a yoke 1|, pivoted as at 12, and having its arm 13 attached to one end of a pull rod 14. The other end of this pull rod is pivotally fastened to foot lever is which, as hereinbefore described, may be manipulated to control the setting of throttle l6. Thus, when foot lever [B is rocked in one direction or the other, this movement is translated into rotary movement of shaft 61, so that a pointer 15 fastened to the upper end thereof, and registering with a dial 16 on the face of brace flange 56 will indicate the value of the throttle setting.

Thus if the several dials 55, 81 and 16 are so marked as to indicate an optimum combination of rotor blade angle of attack value, throttle setting and rotor inclination value, it is a relatively simple matter for the pilot to adjust the foot levers l1, l8 and I9 until the indicators controlled thereby register with the graduations corresponding to such optimum values. Inasmuch as these optimum values can be found empirically, the rotor blades and engine R. P. M. can be quickly and easily correlated to maintain the helicopter in hovering condition at highest efficiency.

Thus it may be seen that I have provided an instrument for helicopters which fulfills the several objects set forth hereinabove in a thoroughly practical and efiicient manner.

As many possible embodiments may be made of the above invention, and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawing is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In apparatus of the character described, the combination with helicopter rotor and engine control levers of an indicator for each of said levers, means connecting each of said levers to its respective indicator so that movement of any control lever is reflected by corresponding movement of its indicator whereby the pilot can observe momentary values of engine and rotor conditions, and means associated with said indicators for indicating to the pilot the attainment of predetermined optimum values for the rotor and engine operative conditions at which the helicopter is most efiiciently maintained in a condition of flight, the means which connects each of said levers to its respective indicator including cooperating cam and lever means, each lever bein connected to one of said control levers and each cam being connected to the corresponding indicator.

2. Apparatus according to claim 1, wherein the connections between said cams and their respective indicators comprise concentrically arranged relatively rotatable tubular members.

JOSEPH S. PECKER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

